Emulsification of a fluid stream occurs by introducing air or gas into the fluid stream, and is beneficial in many applications. For example, it is known to form an emulsion of air with fuel flowing to the carburetor to an internal combustion engine, with the benefit of increasing the efficiency of combustion. The more homogeneous and complete the air is emulsified with the fuel, the more efficient the combustion process will be. Combustion that is more efficient results in better performance with reduced pollution and emissions. Emulsification of a fuel charge with air is beneficial not only in standard combustion engines, but also in other applications such as jet engines, turbines, home heating systems, paint spraying, perfume dispensing, and the like.
Many prior art systems have attempted, without success, to achieve complete fuel/air emulsification. Most of those systems relate to emulsification of fuel with air for an internal combustion engine. Some such systems attempt to emulsify the fuel downstream of the venturi region of a carburetor, while other such systems attempt emulsification within the venturi region. Still other systems attempt emulsification at the point of fuel delivery. Those prior art systems fail to completely, or homogeneously, emulsify the air and fuel mixture.
FIGS. 1 and 1A are simplified diagrams depicting a standard carburetor having a known emulsification system as used in commercially available Holley.RTM. carburetors. Several references discuss the general subject of carburetor operation. See, for example, Super Tuning and Modifying Holley Carburetors, by Dave Emanuel (S-A Design Books, E. Brea, Calif., 1988), and Holley Carburetors, by Mike Urich and Bill Fisher (HP Books, Los Angeles, Calif., 1987). Both of those books are incorporated herein by reference. Their descriptions of carburetor operation include short discussions on the importance and operation of an emulsion tube in a carburetor.
In the normal operation of a carburetor, the fuel 8 is delivered from a source 10 to a float bowl 12. A float 14 meters the amount of fuel retained in the bowl through a valve system such as a needle and seat assembly 15. The fuel enters a main well 18 through a power valve circuit 16 and/or a main jet 17. The downward stroke of a piston in the engine creates a differential between atmospheric pressure and the pressure in the engine cylinder. The pressure differential creates a partial vacuum in the venturi region 22 of the carburetor and draws the intake air 23 through the venturi. The venturi effect causes the fuel to discharge through nozzle 20 forming a mixture 24 of ambient air and fuel. This air-fuel mixture passes through throttle valve 25 and the intake manifold system to the cylinders, where it is combusted by engine 26.
The prior art carburetor of FIGS. 1 and 1A include an emulsion tube 28 shown in communication with the main well 18 through one or more air channels or ports 30. The emulsion tube 28 obtains air from an air intake orifice 32, which is typically located upstream of the venturi portion of the carburetor. The mixing force of the air attempts to break down the fuel into an air/fuel mixture before it enters the venturi region of the carburetor. However, the mixing is not homogeneous or complete, and is only partially effective.
More specifically, the deficiency in the design of FIGS. 1 and 1A results primarily because the walls of the main well 18 and emulsion tube 28 are simple smooth walled cylinders. Therefore, the air introduced into the fuel stream follows a path of least resistance, which in the smooth bore well design, is an uninterrupted path close to the surface of the wall. In FIGS. 1 and 1A, small circles ("o") represent the air and dashes ("-") represent the fuel. An emuslification is represented by a homogeneous distribution of air and fuel. As shown most clearly in FIG. 1A, the air drawn through the emulsion tube 28 mixes with the fuel only in a local or limited area close to the smooth walls of the main well 18. There are no provisions in the main well 18 to keep the air and fuel in a frothy emulsified state or to continuously direct, redirect or tumble the air back into the flowing fuel 8. Therefore, the air-fuel mixture remains primarily in a stratified form with only incomplete or partial emulsification of the fuel occurring at the areas where air enters air inlets or bleed holes 30 of the main well 18.
Other prior art is likewise not successful at fully emulsifying the air-fuel mixture. For example, U.S. Pat. No. 3,685,808 to Bodai describes a fuel delivery system that attempts to emulsify the fuel by introducing supersonic swirled air through a single air inlet positioned tangent to the end of the fuel nozzle. However, in actuality, the air does not swirl at all, but takes the shortest route by primarily flowing straight through and following the smooth contour of the fuel delivery tube. The air and fuel thus remain in a relatively stratified form. There will be some fuel aeration at the point where the non-swirling air enters the fuel delivery tube through the single air inlet. However, the complete air-fuel mixture is at best only partially aerated.
U.S. Pat. No. 1,041,480 to Kaley purports to disclose a system that aggravates the intake air in the air channel down stream from the fuel nozzle. The wall of the intake air channel of the Kaley patent is threaded or knurled in an attempt to aggravate the intake air prior to mixing with the fuel. In reality the knurled or threaded surface of the intake air channel causes an unwanted "throttling" effect thus restricting the flow or volume of air and fuel delivered to the combustion area.
U.S. Pat. No. 4,217,313 to Dmitrievsky et al. attempts to accomplish the creation of an air-fuel emulsion by trying to swirl air down-stream from a venturi. Air above the throttle valve, and at the same pressure as the upstream throttle chamber, passes around the throttle in a separate air passage to a circular air chamber below the venturi. Dmitrievsky teaches that the air pressures both above the throttle valve and in separate air chamber below the venturi are higher than that of the down-stream throttle chamber. Therefore, the intake air above the throttle valve is supposedly forced into the air passage leading to the circular air chamber. Dmitrievsky presumes that the circular shape of the air chamber will cause the air to swirl vigorously and exit an annular passageway. A depression in the annular passage (venturi effect) then causes the air to move at sonic velocity. Dmitrievsky teaches that because the air is at sonic velocity and swirling, the invention achieves fine atomization and uniform mixing of the air and fuel. However, conventional testing has established that the swirling of air in such a configuration is almost nonexistent. As a result, the air-fuel mixture will in all likelihood remain in the same stratified state as the mixture immediately down-stream of the venturi, and thus, is of very little benefit to fuel emulsification.
Italian Patent 434,484 to Bertolotti teaches a fuel/air mixing system that purportedly swirls the air within the main throttle area of the venturi. However, this system does little to promote fuel emulsion. Conventional flow bench testing has determined that any type of rough or threaded surface in the venturi region will only restrict the air flow through the venturi, thus slowing down the throttle response and reducing engine horsepower capabilities.
U.S. Pat. No. 1,969,960 to Blum relates to a drink dispenser used to aerate and mix a liquid drink. The Blum device attempts to mix and aerate the liquid by introducing two fluids (air and a drinking fluid) of equal pressures but different viscosity into a common chamber located above a dispenser nozzle containing a spiral band. However, because the liquids are of different viscosity, the volume of each liquid passing through the dispenser nozzle will be different. In practice, this causes the heavier liquid to separate unevenly from the thinner liquid, and little aeration of the drinking liquid occurs within the nozzle chamber. Most, if not all, of the aeration occurs at the sharp beveled end of the nozzle dispenser that forces the liquid from one side of the dispenser nozzle to the other side of the dispenser nozzle.
U.S. Pat. No. 2,034,430 to Farrow describes a carburetor system in which air enters a mixing chamber through a throttle valve. Within the mixing chamber is a cone having an apex faced in the direction of the main intake air. The surface of the cone is comprised of a grid of longitudinal ribs and a series of circular steps. Fuel enters the mixing chamber through a helix shaped passageway and distributes onto the surface of the cone's ribs and steps. This is supposed to uniformly cover the cone with a thin liquid film of fuel separated into finely divided particles. When main air from the intake enters the mixing chamber, the fuel vaporizes, resulting in a homogeneous air-fuel mixture. This process, known as air stream atomization, does not use a secondary inlet air for fuel emulsification. However, the device does use a secondary idle air intake, but that has nothing to do with fuel emulsification.
U.S. Pat. No. 2,985,524 to Jacobus describes a device that attaches to the delivery side or lower end of the carburetor barrel. The device primarily consists of a nozzle body on the delivery side of the carburetor. The nozzle body that is comprised of a plurality of helical channels that purportedly cause the fuel to spiral or swirl before entering the venturi chamber. However, at no point is air introduced into this delivery system. Therefore, there is no possibility for increased air-fuel emulsification.
In view of the above prior art, the need exists to improve fuel atomization by more effective emulsification of an air-fuel mixture. The emulsification improvement system should have the ability to be easily and readily adapted into most existing fluid delivery systems. Although the specification is largely directed to improved emulsification systems and methods used in carburetors for internal combustion engines, the invention is also applicable other systems where it is desirable to have enhanced emulsification.